The development of a new technique to improve the performance of matrix assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry is proposed. This new method could significantly extend the high resolution mass range of linear spectrometers, and would therefore make TOF much more useful for the analysis of complex mixtures of heavy biomolecules. Our numerical calculations show that the performance of a simple, linear TOF spectrometer can be improved to the level of the much more complex and expensive reflection systems. This proposal describes a new approach for optimizing the performance of linear time-of-flight (TOF) spectrometers without alterations to the existing structure. During Phase I we will use this technique to improve TDA Research Inc.'s current spectrometer to experimentally show the feasibility of the concept. PROPOSED COMMERCIAL APPLICATIONS: This technology will offer significant improvements to TOF mass spectrometers through the use of an inexpensive add-on device. The increased high resolution mass range will then make TOF-MS a more powerful tool for the analysis of biomolecules.